I have the original Ultralite, connected (and powered) by a PCI firewire card with a TI chipset, running on a PC with Windows 7 32 bit. Occasionally, the sound will start clicking and all the meters (including a letter "M" between the 8 and L) will start flashing. When it stops it sits quietly, however, if there is any audio (windows sounds, MP3s, video etc.) the sound will switch from the static/popping noises to a very loud, mechanical hiss that sounds like it will pop the speakers. This happens regardless of whether I'm using the computer or if it's just sitting idle.

I've tried replacing the firewire cable, reinstalling the firmware, updating all the drivers in the system (related to the audio or not) and even adjusting settings. The unit ran fine for several months and has just started doing this. Does anyone have any ideas how to fix this issue?

I changed the driver from "1394 OHCI Compliant Host Controller" to "1394 OHCI Compliant Host Controller (legacy)". There were only three options in there so hopefully I've grabbed the one you recommended.

This only happens about twice a day so I won't know for sure if the fix worked, at least for a day or two.

Was this a know issue with the new drivers conflicting with the "1394 OHCI Compliant Host Controller" drivers?

It's very common under Windows 7 for users needing to use the legacy driver for perfect stability, depending on the actual hardware adapter. It took me a good week or so of figuring things out for myself when Windows 7 first hit beta. I have the Traveler. Countless users have since found success from this.

Let us know how it goes. There will be other suggestions for sure if needed.

Ah man... it didn't work. I was in the kitchen and I heard the computer making the clicking noise from the other room. I went in, pressed play on iTunes (to test the audio) and sure enough it just made a hissing noise.

Yes, the next likelihood of causing this issue is whichever antivirus you have installed.

Quite often, removing the antivirus solves this same issue. So to do so in the best manner, you can find the specific removal tool .exe for whichever one you have and then use it in safe mode. Reboot and test. If it's all good, I recommend installing MSE to replace the original a/v.

Scroll to the bottom three or four posts to see someone that I helped fixed this exact issue regarding their a/v:

I'll certainly give that a try. The antivirus suite I'm currently using (F-Secure), slows down the load time on videos. Drives me nuts. I'm more than happy to jump ship and try a new one. If it will fix my MOTU problem, all the better!

Well, I switched back to the antivirus I used to use and the problem is still occurring. I did get a quick video of it. After the clicking started, I tried to play music so you can hear the sound it makes every time the system makes a sound.

F-Secure is a lesser known name in the industry than others, and I seriously would not be surprised if it was part of the issue.

You didn't state what the new a/v is, so that too can be part of this issue.

What you can do is type msconfig in the start menu then press enter.

Go to Startup tab and check the box to "disable all".

Then go to Services tab, check the box to "Hide all Microsoft services" then click disable all. Hit ok then reboot an test. This will either confirm or deny other software causing issues.

When done testing, you can set things back to how they were. If it was successful, you can do so one or a little at a time, to try to isolate the issue.

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Other than that, it's always good practice to make sure the motherboard bios is updated to newest, along with all drivers to everything, especially motherboard/chipset related. You can get these from the motherboard manufacturer's website. Or even better for chipset, you can find which you have, and then go to NVIDIA, AMD, Intel etc...to get latest chipset drivers.

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If you still require some troubleshooting help, you can type msinfo32 in the start menu then press enter. On the screen that opens, hit file | save.Zip or rar the saved file and upload to Megaupload.com, then paste a link here.

I've updated everything I can. I should mention that I'm a "computer guy" and am familiar with different hardware issues and the correct solutions. However, in this case, I thought it best to check and see if this was a known issue with a proved solution.

The reason I re-installed Avira is that it was on the system, with the MOTU, for a very long time incident free. I figured that, it didn't cause any troubles with the MOTU previous to these issues, so it should be fine to put it back on while I sort things out. Basically, my thinking was that I didn't want to throw anything new or unknown into the mix.

Granted, it does make much more sense to strip the system and run it like that, slowly adding things back and waiting for the problem to occur, however, this is a difficult problem to trouble shoot. It only seems to happen once or twice a day and I have had the odd day where it doesn't happen at all. I lack the time and resources to run my computer, sans services and apps, adding things back once every few days while I wait for the MOTU to screw up.

As you seem to feel that the antivirus is still the biggest contender for the cause of this issue, I'm inclined to go ahead with your suggestion of installing MSE. It could very well be that one of the new updates to the antivirus is doing a scan that is messing with things. I'll give your suggestion a try and let you know how I make out, either way.

I was able to get the problem to occur, partially, by playing a large .mkv file. When ever there was a lot of audio, the system would make the crackling and loud noise, then suddenly be OK for a few seconds. I tried it three or four times and it did it every time. This will certainly make troubleshooting easier, now that I can recreate the issue.

I'm now leaning toward the Firewire card or the bus itself as the issue.

I will continue to update my results here, for prosperity. If I can fix this, it may help out others with the same issue.

"If you still require some troubleshooting help, you can type msinfo32 in the start menu then press enter. On the screen that opens, hit file | save.Zip or rar the saved file and upload to Megaupload.com, then paste a link here."